1. Field
Aspects of the present disclosure relate to cathodes, methods of preparing the same, and lithium batteries including the cathodes.
2. Description of the Related Art
For use in various small and high-performing devices, lithium batteries are required to have a high energy density, in addition to small-volume and lightweight characteristics. In addition, for use in electric vehicles, cyclic characteristics of a lithium battery at room temperature and at high temperature need to be regarded as a critical factor. To realize a lithium battery satisfying the characteristics described above, cathode active materials having various layered structures are being reviewed.
Lithium cobalt oxides are commercially available cathode active materials. Lithium cobalt oxides are expensive, have an effective capacity that is about 50% of their theoretical capacity, and have a driving voltage of about 4 V. An example of such lithium cobalt oxides is LiCoO2.
Lithium nickel cobalt manganese oxides have an effective capacity that is similar to that of a lithium cobalt oxide, is inexpensive and highly stable, and have a driving voltage of about 4 V. An example of such lithium nickel cobalt manganese oxides is LiNi1/3Co1/3Mn1/3O2.
However, a transition metal is released from cathode active materials having layered structures during high-temperature driving. The release of the transition metal leads to a low charge and discharge efficiency and a short lifetime. Accordingly, there is a need to develop a method of suppressing the release of a transition metal at high temperature.